You might be able to have a suitable can or plug or something ready when you remove your upper radiator hose from the thermostat neck. I believe that the upper approx. 1/4 of the radiator is above the level of the thermostat housing on the block, which makes for quite a bit of a mess all over things. Maybe the best way to go is remove the lower hose until you get enough coolant out that you can do the upper one dry. This will allow you to clean out the land that the thermostat gasket sits in in both the housing and on the block, an item that I've found to be important. The other strongly urged advice about not overtightening the two nuts that hold the housing in place are dead on as well. (Please don't ask where that three hours went learning this the hard way..) And, as always, don't leave anti-freeze around for children and pets to get involved with, but I'm sure you know that already.I put a dab of anti-seize on the studs that hold the housing before I stick everything back together.